X-ray tube anode



March 5, 1935. 9 H. B, MCEUEN 1,993,376

X-RAY TUBE ANODE Filed Nov. 20, 1933 INVENTOR. JAE. (Ewen W/ W A TTORN E YS.

Patented Mar. 5, 1935 UNITED STATES PATENT OFFICE 1 X-RAY TUBE ANODE Harry B. McEuen, Jacksonville, Fla.

Application November 20, 1933, Serial No. 698,880

' Claims.

5 advantage in the accepted type of anode for X-ray tubes, and particularly in the mechanical connection between the button proper (usually of tungsten) and the metallic backing therefor (usually of copper). Incident to the relatively small area of the button in thermal contact with the copper in the accepted type of anode, any overheating of the button will, by reason of this limited thermal contact with the backing, cause melting of the. backing,with consequent destruction of the tube, or complete separation of the button.

The primary object of the present invention is, therefore, to materially increase the thermal contact between the button and backing, and to utilize this thermal contact increase alreato materially enlarge the strength and character of the mechanical connection between the button and the backing. e

A further object of the invention is the production' of an anode that will increase the amount of load in voltage and milliamperage that may be used in a given focal area, relative to the conventional button type of anode of like focal area, and further to provide a'constr'uction in which cracks developing in the button are prevented from extending through the edge of the button. 4

The invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a broken longitudinal section of an anode constructed in accordance with the present invention.

Fig. 2 is a face view of the same.

Fig. 3 is a face view of a modified form.

Fig. 4 is a broken longitudinal section of the improved anode, showing a. further form of the invention.

Fig. 5 is a View similar to Fig. 4 showing a further modification.

Fig. 6 is a longitudinal section of a further modification of the invention.

Fig. 7 is an elevation of the rear face of the button of the form shown in Fig. 6.

, The invention is shown in several forms, all directed generallyto the increase of thermal contact between the button and the backing, and each presenting particular characteristics of peculiar and important advantage in itself.

With particular reference to Figs. 1 and 2. a flat type of button 1 is shown as carried by a backing 2. In this form the button is formed near its peripheral edge with a series of relative small openings 3, extending through the button, and preferably countersunk at the outer ends. The backing is, as usual, cast under vacuum'for juncture with the button and under these conditions, the material of the backing, usually copper, fills the openings 3, in the form of headed pins 4, which are of course integral with the backing.

The openings 3 in the button are of course to be formed to avoid the focal area on the face of the anode, and where, as shown in Fig. 2, the anode is shown as a line focus tube anode, with the focal area indicated at 5, the button may be formed with additional rectangular or other shaped openings 6, through which integral portions of the backing serve as additional mechanical binders between the button and backing, with, of course, increased thermal contact area.

Fig. 3 shows a face view of a button having a focal area at 7. In this form, the button may be formed, beyond this area,'with series of openings, here shown as concentric rows 8, for the reception of the integral portions of the backa ing. It is to be understood that the openings formed for the reception of integral parts of the backing, while shown as circular and rectangular in cross section, may be otherwise formed optionally, so long as integral portions of the backing extend through integral portions of the button to form an intimate mechanical connection.

The invention in its application to anodes especially designed for therapy tube construction in which there is a relatively large focal area, is illustrated more particularly in Figs. 4 and 5. Here the button is formed with'an annular flange extending rearwardly from and coinciclent with its edge. The .button, as 9, is indicated as circular, and the flange 10 as coincident with the peripheral edge of the button.' The flange 10 of this formed button is provided with a series of openings 11, a single series being shown in Fig. 4 and a multiple series being shown in Fig. 5. These openings 11. whether in single or multiple series, may be in any form in cross section, and optionally countersunk. Preferably, however, the openings are circular in crosssection and countersunk, and while, where the openings are in multiple series, as in Fig. 5,'the respective sets of openings, indicated at 11 and 12, may be aligned axially of the button, or in staggered relation. Of course in this form the backing, in its casting unity with the button, will find its way through the respective openings 11 (Fig. 4) and 11 and 12 (Fig. 5), providing integral pins 13 as mechanical connectors.

In the form shown in Figs. 6 and '7, the anode face or button is of greater diameter than the backing, such button 14, being for the purposes of this invention, integrally formed on its rear face with a series of rearwardly extending flanges 15, formed with openings 16, for the reception of the integral pins 17 of the backing 18. While the flanges 15 are shown as of concentric interrupted type, it is to be understood that they may be annular, diametric, radial, or flat in any desired angle to the diameter. These forms are so obvious that the illustration of the concentric flanges will be suflicient. Of course, in this type, some of the flanges will be embedded in the ma.- terial of the backing, and others, as illustrated, will be at the edge of the backing. Again, the openings 16 may be formed at any desired angle to the particular flange. Thus, some of the openings may be at right angles to the plane of the flange, while others, as indicated at 19, Fig. 6, may be at other than a right angle to the flange. Obviously with angled openings, the mechanical strength of the connection is increased.

In each and every type described, the mechanical strength of the connectionbetween the button and the backing is materially increased over the conventional method of connection, and at the same time the thermal contact between the button and the backing is also materially increased. The general advantages of the increased binding connection and increased thermal contact will be obvious to the skilled roentgenologist, but the improvements present additional advantages which will be briefly referred to.

In the conventional means for securing the button to'the backing, there is a relatively small area of contact. This frequently results in over-,

heating of the backing, causing melting of the backing, with destruction of the tube, and particularly in treatment tubes with large focal areas, or the overloading of small area fine focus tubes, incident to the unequal expansion and contraction of the button and the backing, the button will buckle, separating in part from the backing, concentrating the heat in a relatively small area of the backing, and the button separates entirely from the backing.

If, in the forms shown in Figs. 1, 2, and 3, there is overheating with a tendency toaffect the backing, the first signs of such melting will occur at the uppermost points of connection. This would result in a volatilization of the exposed copper points in thisarea, and the tube would become gassy and cranky, notifying the operator of the difficulty long before there was any possibility of separation of the button and backing. Furthermore, in these forms any tendency of cracking in the button would be prevented from extending through the edge of the button, as the openings would prevent the crack crossing. In this connection it is to noted that the arrangement of the respective series of openings, as shown in Fig. 3, will tend to interrupt the continuance of a crack formed at the focal area and radiating in any direction.

In the remaining forms of the invention there is no backing exposed on the face of the button,

hence complete elimination of the danger of gassing the tube, and permitting increase of load in voltage and milliamperage without the liabilities incident to conventional construction.

Thus, the improved construction, increases thermal contact between the button and backing, materially strengthens the mechanical connection between these parts, and affords the additional safety factors noted without materially increasing the cost of production or increase in material.

While the backing is shown solid, any conventional form that will admit of the particularly defined arrangements may be used. Further, the invention is not concerned with any particular means for cooling the backing, and contemplates the use of any and all possible means to this end, it being understood and admitted that some extraneous means for cooling are highly desirable and important.

What is claimed is:

1. An anode for an X-ray tube having the button formed with a series of openings extending entirely through the material of the button and arranged concentric with and wholly beyond the focal area of the button, and a backing for the button having integral portions projecting into and completely filling said openings, whereby to preserve the focal area of the button of full normal thickness and strength, increase the relative heat conductingarea of the backing, and prevent separation of the button and backing.

2. An anode for an X-ray tube having the button formed with a series of openings extending entirely through the material of the button and arranged concentric with and wholly beyond the focal area of the button, and a backing for the button having integral portions projecting into and completely filling said openings, the ends of the openings in the button and the cooperating'portions of the backing being mechanically formed to prevent separation of the button and backing.

3. An anode for an X-ray tube having the button formed with a series of openings opening through the face .of the button concentric with and wholly beyond the focal area of the button, and an integral backing having projections extending through and filling said openings, the openings in the button serving to prevent cracks in said button from extending through the edge of the button.

4. An anode for X-ray tubes, including a button formed with a series of openings extending entirely through the face of the button concentric with and wholly beyond the focal area of the button, the ends of the openings in the plane of the face of the button being countersunk, and a backing having integral projections extending through and completely filling the openings.

5. An anode for X-ray tubes, comprising a button formed with a plurality of rows of openings extending entirely through the button and each concentric with and wholly beyond the focal area of the button, and a backing having integral projections extending through and completely filling the openings, the openings of each row being radially offset with respect to the openings of the other row to provide a limit for any crack starting in the focal area of the button.

HARRY B. McEUEN. [1..s.] 

